Manner of and apparatus for ascertaining the mean length of cotton or like fibers and/or the mean weight per unit of length of similar fibers



Feb. 8, 1938. c. NANJUNDAYYA 2,107,616

MEAN LENGTH OF COTTON OR LIKE IGHT PER UNIT OF LENGTH OF SIMILAR FIBERS MANNER OF AND APPARATUS FOR ASCERTAINING THE FIBERS AND/0R THE MEAN WE Filed May 10, 1954 5 Sheets-Sheet l rf wf Feb. 8, 1938. c. NANJUNDAYYA 2,107,616 MANNER OF AND APPARATUS FOR ASCERTAINING' THE MEAN LENGTH OF COTTON OR LIKE FIBERS AND/0R THE MEAN WEIGHT PER UNIT OF LENGTH OF SIMILAR FIBERS Filed May 10, 1954 s Sheets-Sheet 2 III/I c. NANJUNDAYYA MANNER OF AND APPARATUS FOR ASCERTAINING THE MEAN LENGTH OF COTTON OR LIKE Feb. 8, 1938. 2,107,616

FIBERS AND/OR THE MEAN WEIGHT PER UNIT OF LENGTH OF SIMILAR FIBERS 5 Sheets-Sheet 5 Filed May 10, 1934 ,Zwentor; L. 77anju2 c?ayya W W 4 W Patented F eb. 8, 1938 UNITED STATES MANNER OF AND APPARATUS FOR ASCER- TAINING THE MEAN LENGTH OF COTTON OR LIKE FIBERS AND/OR THE LIEAN WEIGHT PER UNIT OF LENGTH OF SIM- ILAR FIBERS Chandrashekariya Nanjundayya, Matunga, Bombay, British India, assignor to The Indian Central Cotton Committee, Bombay, British India, a corporation under the Indian Cotton Cess Act 1923 Application May 10, 1934, Serial No. 724,958 In British India May 19, 1933 7 Claims.

This invention relates to an improved manner and process for ascertaining the mean length of fibers and the mean fiber weight per unit of length of raw cotton, or like textile fibers. It also includes apparatus whereby the said improved manner or process may be efliciently carried out.

With the methods now in vogue for the determination of these two properties it is necessary first to carry out two or more independent opera- 10 tions. According to one known method, a somewhat complicated and expensive machine is required, and according to each of the known methods reliance has to be placed upon the accuracy of manipulation and the judgment of the operator in arranging the fibers and drawing conclusions from his observations.

One object of the present invention is to provide a manner, process and apparatus, by means of which these two properties for any cotton or like fiber can be determined as a result of a series of operations, and by these means a considerable saving in time and labour be eiTect-ed.

According to the current methods of determining the mean fiber length of a cotton commonly in use, dependence is based upon sorting the cotton into its constituent fibers of different lengths and estimating, either by means of a balance or on a rule block, the relative amounts of the fibers falling into each length.

In these known methods the fact that the fiber varies in thickness throughout its length is not taken into consideration. As a general rule cotton fiber is thickest and heaviest per unit of length in the middle of its length, while it is thinner towards the two ends. This variation in thickness may affect the results when estimating the length and thus may affect the results when calculating the mean weight per unit length.

A method of stapling cotton or other fibers has been suggested which consists in cutting a fixed length from substantially all the fibers at or near their middle portion and determining the ratio by weight of the ends. to this middle portion, and thereafter using this ratio in calculating their average length.

In using a method such as last described it was necessary to apply a formula having coefiicients therein (which had to be determined by experience and experiment) if the trade or body length to be determined was to agree with those ascertained by experts in such art and to agree with standard determinations.

These formulas take into consideration average conditions and had not necessarily any fixed relation to the particular sample of fiber being tested.

They also depended on combining the weights of the end groups and applying a formula which only considered the weight and length of the central group of fixed length, and the combined weights of the end groups.

The present invention compares the weights of the end groups, the length of the fibers of one of which is known, and by these means it determines with great accuracy the length of the fibers in the other end group. The determination is not dependent on formulas which have been developed from general considerations and averages of fibers elsewhere, but depends on the characteristics of the actual bunch of fibers under consideration.

One object of this invention is to eliminate, as far as is practically possible, the factor of uncertainty which is due to the fibers being thicker and heavier in the middle of their lengths, and with this object in view, to judge the length by comparing the weights of the two ends of the bunch of fibers having eliminated therefrom a section from the middle portion of the bunch where the fibers are of a different thickness and weight than at the ends. 1

In certain of the known methods it is necessary to draw out fibers using tweezers and pulling the fibers by hand out of a sliver. This hand operation has not the same accuracy and steadiness as may be obtained when mechanical means are employed. One object of the present invention then is to provide apparatus by means of which the bunch of fibers which is to be taken as a sample is mechanically extracted from. a sliver and is mechanically stretched, measured and cut to eliminate, as far as possible, the human element in these operations, and also to facilitate and speed up the operations so that the time and labour necessary to ascertain the mean fiber length and the mean weight per unit of length shall be reduced to a minimum.

The invention will now be described with reference to the accompanying drawings, in which a suitable machine for carrying out the determination of length and unit weight is illustrated in a somewhat diagrammatic manner.

In these drawings:-

Figure 1 is a view, partly in section, of a form which the machine may take.

Figure 2 is a cross section of the machine on line 2-2 of Fig. 1.

Figure 3 is a plan of the machine.

Figure 4 is a cross section on line 4-4 of Fig. 1, and

Figures and (i show details of the rod which enables slow motion to be given to the parts.

A representative sliver is made from the cotton under test by any of the usual methods. This sliver is placed across a set of combs I of any suitable material which engage the sliver, so that a small portion of it is projecting beyond the first comb. The combs l, I are supported by rods IA, iA passing through holes drilled in the metallic uprights of the machine. The ends of therods EA, IA are bent into hooks or rings IB, 5B for convenience and to enable the combs to betaken out for cleaning. The carriage 2 supports tweezers 3, which have springs 3a, and which tweezers may be moved backwards and forwards with their carriage upon the slide of the bed 4. The carriage 2 is first advanced forward towards the end of the sliver engaged by the combs and the fibers projecting beyond a transverse section of the sliver near its end are caught in the jaws 5 of the spring tweezers and may be securely held in the nip of the tweezers by pressing down the eccentric catch 6 as shown in Figure 1. The carriage is then moved backwards, and after drawing out the fibers which have been engaged, the nip of the tweezers is released by raising the said eccentric catch, and these fibers are removed and discarded. This process of engaging the ends of fibers and drawing them out of the sliver and discarding the drawn out fibers is repeated by moving the carriage backwards and forwards and operating the tweezer each time for several times in succession, the process being continued until all the ends of the fibers in the sliver lie along a line parallel to the combs.

When this state of affairs has been reached, the carriage is again advanced forward and a bunch containing all the fibers whose ends-are on this line is caused by the tweezers at their very ends, or approximately within g gnd of an inch of the extreme ends. The bunch of fibers which is held by the tweezer cleared of stray fibers by passing it through a separate comb two or three times.

The next stage of the operation commences by releasing the screw 1 which secures the tweezer upon the carriage 2 and rotating the tweezers through 180, so that the bunch of fibers is now facing a second carriage 8 which is at the other end of the slide bed. In order to make certain that the tweezer 3 has been rotated through exactly 180, two fine lines 26, 26 may be engraved upon the upper surface of the carriage 2 between which lines the tweezer lies uniformly when it has been rotated through 180. It is essential that the nip of the tweezers shail be perpendicular to the length of the bed of the slide, so that the measurements taken on the fibers shall be accurate.

The carriage 2 is now advanced forward until it occupies a position somewhere about the middle of the slide bed. The sagging end of the bunch of fibers opposite to that which is held by the tweezer and at which end fibers of different length project, is gently lifted from below and the bunch of fibers is placed upon a strip of paper resting upon a piece of linoleum upon the bridge piece 9. This bridge piece is directly below the cutter or guillotine arrangement which will be described later.

The carriage 2 is fixed to a block 29 and is provided with a clamping screw 3lA. When this screw is turned by using the handle 31B below, the carriage is clamped to the central rod 24,

which contains a strong steel spring 25 at one end may slide.

and can be moved forwards or backwards by the slow motion screw lil, thereby moving the carriage 2 with it. The central rod 2a is hollow at one end and fits onto a hub to upon which it At the other end the rod it enters a cavity 38A and this end engages the end lfiA of the slow motion screw 50. The hollow end of the rod 24 contains a strong spring 25 which forces the rod to the right. When, on the other hand, the clamping screw 36A is released, the carriage is free to slide along the base through larger distances. A similar clamping device 32A with handle 32B is attached to the second carriage 8 which can also be moved either through small distances by the slow motion screw it] or through large distances by hand. The carriage 2 is now traversed, using the slow motion screw III, or other suitable means, to adjust the distance between the nip of the tweezers 3 and the nearer, H, of the two blades which are mounted in the cutter or guillotine l2.

This distance is accurately read by the use of the scale l3 and the Vernier scale 13a. This Vernier is fixed to the carriage 2, whilst the scale I3 is fixed to the edge of the slide bed t. The carriage 2 is securely clamped in position.

The carriage 8 is now advanced forward and the free end of the bunch of fibers is nipped between the jaws of the second tweezer M- which is fixed to carriage 8. The jaws of this tweezer are made to nip by operating the eccentric catch I5. The second carriage 8 is gently moved backwards by hand until the bunch of fibers is stretched, so that on the 'one hand there isno crimp in the bunch, and on the other hand, the fibers are not unduly stretched beyond their proper length. After straightening the fibers in this manner, the carriage 8 is then clamped in position.

Any suitable type of screw to which the carriage 2 may be clamped may be provided which will enable this carriage to be traversed backwards and forwards with suitable rapidity in the necessary stages of the manipulation, and which will enable its position to be very accurately ad.- justed in relation to the position of the guillotine knives when so desired.

' When the bunch of fibers is thus held between the two tweezers 3 and I4 and is suitably straightened or slightly stretched, it will be found to just rest upon the paper and linoleum placed upon the bridge piece 9. The cutter I2 is now swung down using the handle ll, and the bunch of fibers is cut into three unequal portions. The piece of linoleum on which the paper and fibers rest serves the useful purpose of yielding slightly when pressure is applied on the cutter, thereby allowing the fibers to be cut neatly without blunting the cutting blades. It is preferable to use a piece of blue paper, so that the white cotton is most suitable for the particular class of cotton under test. As already explained, the spacing of these blades when cutting cotton depends upon the staple. It is important that both blades should cut through every fiber in the bunch and in cutting cotton the blades may be 2,107,616 spaced Afapart for the shortest staple Indian cotton, such, for instance as Bengals which are to A, long; but may be spaced a greater distance apart for the longer staples, such for instance as Indian PA 2891 which is from 1" to 1 and 9 inch long, or for Egyptian cotton, which is longer still. For the longer staple cotton the two razor blades may be spaced apart convenient- 1y a distance of The razor blades are held in position by two loose slide plates 20 and 2| and two screws 21, 21 which pass through holes in the said plates and the blades and a fixed part and may be held fast by nuts 28, 28. One plate l9 of the cutter is an abutment plate permanently attached to the cutter so that the position of the nearer blade I I shall be exactly ascertained between said abutment plate I9 and the nearer loose side plate 20, whilst the other side plate 2| on the further side of the other razor blade I8 is also a loose plate which is clamped by the bolts 21, 21 which pass through it. The whole assembly with the two razor blades, and suitable packings I 9a to give the necessary spacings between the blades, may be clamped together by the said bolts and nuts 21, 2B.

In the particular embodiment shown the cutter is operated by means of the handle I! and the cutting blades are fixed in a part which is pivoted on the pin 22, which pin passes through two lugs 23, fixed integral to the abutment plate i9 thus enabling the blades topivot in the plane perpendicular to the length of the slide bed, so that the blades are able to cut the fibers cleanly, owing to their edges taking up a horizontal position when the pressure is applied thereto.

When the bunch of fibers has been cut, the cutter is swung up and the strip of paper supporting the central portion of the bunch, which usually comes off along with the cutter, is carefully removed, together with all the cut fibers adhering thereto and the said fibers, whose length is known, are placed aside to be weighed. Similarly, the two other portions of the bunch between the two tweezers and the blades are carefully removed and placed aside in separate groups.

The whole process of extracting a bunch of fibers from the sliver, combing the bunch toremove stray fibers, stretching it between the tweezers where it is in place above the bridge and cutting it into three portions may be repeated three or four times and the cut portions of each bunch be added to the'co-rresponding groups.

For each particular staple of cotton the distance between the nearer blade II and the nip 5 of the tweezer 3 is kept constant. Similarly, the same thickness of packing plates is used between the two razor blades for each particular staple of cotton.

After having carried out the operations detailed above, there will thus be three groups of cut fibers, in two of which the cut fibers will be all of the same length in each group, which length will be definitely known. These are (A) those between the tweezer 3 and the blade II and (B) those between the two blades. Let these lengths be Z1 and 12 respectively. In the third group, which came between the razor blade l8 and the tweezer M, the fibers will not be of the same length but of diifering lengths. Let us denote their average length, which is as yet unknown, by at. The three groups are now taken separately and their weights are determined on a sensitive torsion balance, for example a torsion balance having a range of 0-5 mgms. Let these weights be 1D], (for the group having length 11,) wz (for the group having length Z2) and 1113 for the group having average length 3:. Then W3 X 3T2 or e x= I X 1 The mean length of the cotton L is therefore given by the equation The total weight of the fibers w in all the bunches which were cut is given by the equation In order to determine the fiber weight per unit length Y, the fibers in the first group are placed between two glass slides with their ends just projecting out, and a count of all the fibers is made. Let the total number thus counted be N. Then the fiber weight per unit length will be To ensure that no fibers are lost during weighing, the count of their total number is made before the first group is weighed on the torsion balance.

The use of a sensitive torsion balance is recommended because it is easy and quick to manipulate, and, for all practical purposes, gives fairly accurate results. In view of the fact, however, that the elastic properties of its spring are likely to change slightly with lapse of time, it is advisable to calibrate the torsion balance at regular intervals against a quartz micro-balance, if it is available. The calibration can be easily performed by weighing the same half a dozen or so bunches of fibers on the two balances. These bunches should preferably weigh approximately 1, 2, 3, 4, and 5 mgms. so as to cover the entire range of the torsion balance. If differences of appreciable magnitude are found to exist between the two sets of weighings, a table of corrections,

to be applied as occasion demands, should be prepared.

It is of course to be understood that the invention is not restricted to one in which the apparatus is limited to that described, as it will be realized that the details of the different parts may be modified, for example, any suitably guided guillotine arrangement may be used for dividing the fibers. The carriages 2 and 8 may be moved by hand along the slide beds and be clamped when desired in any suitable place along such bed, and some sort of screw, such as the tangent screw which is common on theodolites, be used for fine adjustments of position.

The invention has mainly been developed for obtaining the length and. the weight per unit length of cotton fibers; but it isnot necessarily restricted to use with cotton, although with other fibers the problem to be solved may be somewhat different. With cotton fibers the weight per unit length of the middle portion of each individual fiber is more than that at the two ends. The weight per unit length-at the two ends may vary somewhat and one end taper off more gradually in thickness than the other end, but it will be found that in makingthe sliver the different fibers contained therein face different directions and will average up.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:--

1. A manner of ascertaining the mean fiber length of raw cotton or other textile fibers, which consists in taking a representative sample of the fibers, combing it out, selecting therefrom a bunch of fibers with aligned ends, the ends of uneven length being all at the further end of the bunch, cutting off a measured length of the bunch from the aligned end and also a measured length from the centre of the bunch by dividing the bunch at two points, thereby forming three groups, weighing the two end groups separately and determining the ratio of the weight of the uneven ends in the third group to the weight of the fibers portions in the first group, which fiber portions are of known length to obtain the mean length of the fibers portions in said third group and thus to obtain the mean length of the fibers in the sample.

2. Apparatus for ascertaining the mean fiber length and/ or the mean fiber weight per unit of length of raw cotton or other textile fiber, comprising a slide bed, a tweezer, a carriage mounted on the slide bed and carrying the tweezer thereon, means for causing said tweezerto engage and securely to hold fibers, said carriage being slidable on said bed to draw out certain fibers from a sliver, and a comb at one end of the slide bed adapted to hold the sliver.

3. Apparatus, according to claim 2, having also a scale on said bed showing'the position of said carriage, clamping means for securing the carriage in said position, said position being accu-- 5. Apparatusaccording to claim 2 having also a second carriage associated with the slide bed carrying another tweezer thereon, said first mentioned tweezer being adapted to grip the fibers remaining on the comb and which form the test sample and being revoluble from a position facing said comb to a position facing said second carriage, means being provided for traversing said second carriage and clamping said second carriage in desired position, and having also cutting means in the shape of two cutting knives spaced apart between the carriages, said knives being mounted in such manner that they will out said remaining fibers of the sliver held in the two tweezers, simultaneously along two parallel lines, said lines being at desired measured distances from that end of said fibers which is held in the tweezer mounted on the first said carriage.

6. Apparatus according to claim 2, having also cutting means in the shape of two cutting knives spaced apart, said tweezers being adapted to grip the fibers remaining on the comb and which form the test sample, and being revoluble from a position facing said comb to a positionfacing said cutting means, said knives being mounted in such manner that they will cut the fibers of said test sample simultaneously along two parallel lines, said lines being at desired measured distances from the end of the fibers which is held in the tweezer mounted in the carriage.

'7. Apparatus according to claim 2, having also cutting means in the shape of two cutting knives spaced apart, said tweezers being adapted to grip the fibers remaining on the comb and which form the test sample, and being revoluble from a position facing said comb to a position facing said cutting means, said knives being mounted in such manner that they will cut the fibers of said test sample simultaneously along two parallel lines, said lines being at desired measured distances from the end of the fibers which is held in the tweezer mounted in the carriage, said apparatus having a guillotine arrangement carrying said two knives, the spacing between the two knives being adjustable whereby spacer means of different thickness may be introduced therein.

, CHANDRASl-IEKARIYA NANJUNDAYYA. 

